the victims. ceremoes in new york, virginia, and pennsylvania pay tribute to the 2,760 victims killed when terrorists hijacked four commercial planes and attacked the u.s. in lower manhattan, 9/11 families gather at zuccotti park adjacent to ground zero. throughout the morning as has now become tradition, theim nam of victims will be read and four moments of silence will mark the times each plane hit and each tower fell. the vice president joe biden is attending the ceremony along with city and state leaders and first responders. at the pentagon, president obama delivers remarks and participates ina wreath laying ceremony at the morial site. and in shanksville, pennsylvania, where united flight 93 crashed, first lady michelle obama along with first lady laura bush attend a ceremony to honor the passengers who fought back. meanwhile, plans to rebuild at ground zero are moving forward. the center piece, one world trade center is expected to be completed by 2013. but with each construction step forward, this remains a connection to the past. steel beams pulled from the ground zero rubble were